Imaging element, imaging apparatus, and control method for imaging element

ABSTRACT

An imaging element includes a buffer, an image producing unit, a managing unit, and an output unit. The image producing unit produces an image in the case where an empty capacity of any of plural areas in the buffer exceeds a predetermined threshold value. The managing unit causes an area whose empty capacity exceeds the predetermined threshold value, of the plural areas to retain the image as a buffering image. The output unit extracts the buffering image from the buffer and outputting the buffering image, in order of the retention of the buffering image.

TECHNICAL FIELD

The present technique relates to an imaging element, an imagingapparatus, and a control method for an imaging element. The presenttechnique relates more particularly to an imaging element that includesa frame buffer, an imaging apparatus, and a control method for theimaging element.

BACKGROUND ART

In the past, an imaging apparatus that high-speed-shoots a moving imageat a frame rate higher than a frame rate for reproduction has been usedwhen an object moving at a high speed is imaged. A smooth slow-motionvideo image is acquired by reproducing this moving image at a frame ratethat is lower than that for recording. For example, when a moving imageimaged at a high frame rate of 600 hertz (Hz) is reproduced at a lowframe rate of 60 hertz (Hz), the reproduction time period is elongatedto a 10-fold length of the recording time period and the speed of theaction of the object in the reproduced moving image is reduced to 1/10.When the image data (a frame) high-speed-shot in this manner is outputto a signal processing unit at the high frame rate as it is, the framemay not be completely processed by the signal processing unit whoseprocessing speed is low. An imaging apparatus has therefore beenproposed that temporarily retains a high-speed-shot frame in a memory(that is, buffering) and that outputs the frame to the signal processingunit at a low frame rate (see, e.g., PTL 1).

CITATION LIST Patent Literature [PTL 1]

JP 2008-113126A

SUMMARY Technical Problem

In the above related technique, to prevent any overflow of the memory,the high-speed shooting is executed when a sufficient empty portion ispresent in the memory, and the buffered frame is extracted from thememory and is output when the recording is stopped or the like. In thecase where two sessions of high-speed shooting are executed, the imagingapparatus therefore cannot start the second session of the high-speedshooting until an empty portion is produced in the memory when nosufficient empty portion is present in the memory due to the firstsession of the high-speed shooting. As above, a problem arises that itis difficult to execute the high-speed shooting consecutively in pluralsessions.

The present technique was conceived in view of the above circumstancesand an object thereof is to execute high-speed shooting consecutively inplural sessions using an imaging apparatus that includes a frame buffer.

Solution to Problem

The present technique was completed to solve the above problem and afirst aspect thereof is an imaging element including a buffer that hasplural areas disposed therein, an image producing unit that produces animage in the case where an empty capacity of any of the plural areasexceeds a predetermined threshold value, a managing unit that causes anarea whose empty capacity exceeds the predetermined threshold value, ofthe plural areas to retain the image as a buffering image, and an outputunit that extracts the buffering image from the buffer in order of theretention of the buffering image and outputs the buffering image, and acontrol method for the imaging element. An action is thereby providedthat an image is produced in the case where an empty capacity of any ofplural areas in a buffer exceeds a predetermined threshold value.

Furthermore, in the first aspect, the image producing unit may producethe image as a preview image every time a predetermined cycle elapses ina predetermined normal shooting period and may produce the image as ahigh-speed shooting image every time a cycle that is shorter than thepredetermined cycle elapses in the case where an empty capacity of anyof the plural areas exceeds the predetermined threshold value in ahigh-speed shooting period that is different from the predeterminednormal shooting period, and the managing unit may cause the high-speedshooting image to be retained as the buffering image. An action isthereby provided that a preview image is produced every time apredetermined cycle elapses and a buffering image is retained every timea cycle that is shorter than the predetermined cycle elapses.

Furthermore, in the first aspect, the output unit may further output thepreview image together with the buffering image every time thepredetermined cycle elapses. An action is thereby provided that apreview image is output together with a buffering image every time apredetermined cycle elapses.

Furthermore, in the first aspect, the managing unit may cause the bufferto retain the preview image together with the buffering image and theoutput unit may extract the buffering image and the preview image fromthe buffer in order of the retention of these images and may outputthese images. An action is thereby provided that a buffering image andthe preview image are extracted from the buffer in order of theirretention.

Furthermore, in the first aspect, the output unit may extract thebuffering image from the buffer and may output the buffering image whena predetermined operation is executed. An action is thereby providedthat a buffering image is extracted when a predetermined operation isexecuted.

Furthermore, in the first aspect, the output unit may extract thebuffering image from the buffer and may output the buffering image whenthe high-speed shooting period comes to an end. An action is therebyprovided that a buffering image is extracted when a high-speed shootingperiod comes to an end.

Furthermore, in the first aspect, the output unit may extract the pluralbuffering images and may output these buffering images every time thepredetermined cycle elapses. An action is thereby provided that pluralbuffering images are extracted every time a predetermined cycle elapses.

Furthermore, a second aspect of the present technique is an imagingapparatus including a buffer that has plural areas disposed therein, animage producing unit that produces an image in the case where an emptycapacity of any of the plural areas exceeds a predetermined thresholdvalue, a managing unit that causes an area whose empty capacity exceedsthe predetermined threshold value, of the plural areas to retain theimage as a buffering image, an output unit that extracts the bufferingimage from the buffer in order of the retention of the buffering imageand outputs the buffering image, and a recording unit that records theoutput image. An action is thereby provided that an image is recorded inthe case where an empty capacity of any of plural areas in a bufferexceeds a predetermined threshold value.

Advantageous Effect of Invention

According to the present technique, an excellent effect can be achievedthat an imaging apparatus retaining an image can execute high-speedshooting consecutively in plural sessions. In addition, the effectdescribed in this paragraph is not necessarily limited and may be anyeffect described in the disclosure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram depicting an example of the configuration ofan imaging apparatus in a first embodiment of the present technique.

FIG. 2 is a block diagram depicting an example of the configuration ofan imaging element in the first embodiment of the present technique.

FIG. 3 is a block diagram depicting an example of the configuration of apre-processing unit in the first embodiment of the present technique.

FIG. 4 is a diagram depicting an example of the configuration of a framebuffer in the first embodiment of the present technique.

FIG. 5 is a block diagram depicting an example of the configuration of amanaging unit in the first embodiment of the present technique.

FIG. 6 is a block diagram depicting an example of the configuration of apost-processing unit in the first embodiment of the present technique.

FIG. 7 is an example of a state transition diagram for the imagingapparatus in the first embodiment of the present technique.

FIG. 8 is a timing chart depicting an example of an operation of theimaging apparatus in the first embodiment of the present technique.

FIG. 9 is a diagram depicting an example of variation of a capacity ofthe frame buffer during shooting in the first embodiment of the presenttechnique.

FIG. 10 is a diagram depicting an example of variation of the capacityof the frame buffer after the shooting comes to an end in the firstembodiment of the present technique.

FIG. 11 is a graph depicting an example of variation of an accessdestination of each area in the first embodiment of the presenttechnique.

FIG. 12 is a flowchart depicting an example of an operation of theimaging apparatus in the first embodiment of the present technique.

FIG. 13 is a flowchart depicting an example of an accessing process inthe first embodiment of the present technique.

FIG. 14 is a flowchart depicting an example of a high-speed shootingprocess in the first embodiment of the present technique.

FIG. 15 is a timing chart depicting an example of an operation of animaging element in a first modification example of the first embodimentof the present technique.

FIG. 16 is a timing chart depicting an example of an operation of animaging element in a second modification example of the first embodimentof the present technique.

FIG. 17 is a timing chart depicting an example of an operation of animaging apparatus in a second embodiment of the present technique.

DESCRIPTION OF EMBODIMENTS

Modes for carrying out the present technique (hereinafter, referred toas “embodiments”) will be described below. The description will be madein the following order.

1. First Embodiment (An example where buffering into any of plural areasis executed)

2. Second Embodiment (An example where a recording frame is buffered inany of plural areas and is output in order of shooting)

1. First Embodiment [Example of Configuration of Imaging Apparatus]

FIG. 1 is a block diagram depicting an example of the configuration ofan imaging apparatus 100 in a first embodiment. The imaging apparatus100 is an apparatus that images image data (a frame), and includes animaging lens 110, a displaying unit 120, a control unit 130, a recordingunit 140, an application executing unit 150, and a reproducing unit 160.In addition to digital cameras such as a digital still camera and adigital video camera, a smartphone, a personal computer, and the likeeach having an imaging function are each assumed as the imagingapparatus 100.

The imaging lens 110 is a component that condenses a light beam andleads the light beam to an imaging element 200. The imaging element 200is a component that images a frame by photoelectric-converting the lightbeam from the imaging lens 110. The imaging element 200 images a frameat a specific frame rate and outputs the frame to at least one of thedisplaying unit 120 or the recording unit 140 as a preview frame.

Furthermore, the imaging element 200 produces a frame at a frame ratethat is higher than a frame rate for a preview frame and retains theproduced frame as a buffering frame. The imaging element 200 outputs thebuffering frame to the recording unit 140 when a predetermined operation(such as pressing down an imaging stop button) is executed. In thisregard, the output of the preview frame is continued even during theoutput of the buffering frame.

The displaying unit 120 is a component that displays the preview frame.The control unit 130 is a component that controls the overall imagingapparatus 100. The recording unit 140 is a component that records theframe. The application executing unit 150 is a component that executes apredetermined application. The application executing unit 150 edits theframe in the recording unit 140 and produces a moving image thatincludes a recording frame. The reproducing unit 160 is a component thatreproduces the moving image. The reproducing unit 160 supplies therecording frame at a frame rate that is lower than that employed whenthe buffering frame is imaged, as a reproduction frame to the displayingunit 120.

Concerning the above, the states of the imaging apparatus 100 include ashooting mode and a preview mode. This shooting mode is classified intoa normal shooting mode and a high-speed shooting mode. The normalshooting mode is a mode in which a frame is produced at a frame ratethat is lower than that of the high-speed shooting mode and executes therecording and the displaying for the frame. The high-speed shooting modeis a mode in which a frame is produced at a frame rate that is higherthan that of the normal shooting mode. The preview mode is a mode inwhich a frame is produced at a frame rate that is lower than that of thehigh-speed shooting mode and only the displaying is executed for theframe without executing any recording.

When the power source of the imaging apparatus 100 is turned on, theimaging apparatus 100 transitions into the preview mode. In this previewmode, the control unit 130 causes the imaging element 200 to produce thepreview frame at the frame rate that is lower than that of thehigh-speed shooting mode and to output the preview frame to thedisplaying unit 120. Furthermore, in the preview mode, when the imagingelement 200 retains any buffering frame, the control unit 130 causes theimaging element 200 to output the frame to the recording unit 140.

When an operation of starting recording (such as pressing down arecording start button) is thereafter executed, the imaging apparatus100 transitions into the normal shooting mode from the preview mode. Inthis normal shooting mode, the control unit 130 causes the imagingelement 200 to produce a preview frame at the frame rate that is lowerthan that of the high-speed shooting mode and to output the previewframe to the displaying unit 120 and the recording unit 140.

Furthermore, in the normal shooting mode, when a predetermined condition(such as the case where a scene is changed, or the like) is satisfied,the imaging apparatus 100 furthermore transitions into the high-speedshooting mode. Furthermore, in this high-speed shooting mode, theimaging element 200 produces a frame at the frame rate that is higherthan that of the normal shooting mode, and buffers the frame. In thehigh-speed shooting mode, the control unit 130 causes the imagingelement 200 to output the preview frame at the equal frame rate to thatof the normal shooting mode to the displaying unit 120.

The frame rate in the normal shooting mode is, for example, 30 fps(frames per second) and the frame rate in the normal shooting mode is,for example, 960 fps. It is noted that the frame rates of these modesare not limited to 30 fps and 960 fps only when the frame rate of thehigh-speed shooting mode is higher than that of the normal shootingmode.

In addition, though all the imaging lens 110, the displaying unit 120,the control unit 130, the recording unit 140, the application executingunit 150, and the reproducing unit 160 are arranged in the imagingapparatus 100, these components may be arranged being distributed toplural apparatuses. For example, the imaging lens 110, the control unit130, the recording unit 140, and the application executing unit 150 maybe arranged in a camera module, and the displaying unit 120 and thereproducing unit 160 may be arranged in a reproducing apparatus.

[Example of Configuration of Imaging Element]

FIG. 2 is a block diagram depicting an example of the configuration ofthe imaging element 200 in the first embodiment. The imaging element 200includes a scanning unit 210, a pixel array unit 220, an AD (Analog toDigital) converting unit 230, a pre-processing unit 240, and a managingunit 250. The imaging element 200 further includes a memory controller260, a frame buffer 270, a post-processing unit 280, and an outputinterface 290.

The scanning unit 210 is a component that drives the pixel array unit220. The scanning unit 210 starts driving the pixel array unit 220 inaccordance with a control signal from the control unit 130. This controlsignal includes, for example, a signal that indicates whether theimaging apparatus 100 is in the preview mode or the shooting mode.

The pixel array unit 220 is a component that produces an image signal.The pixel array unit 220 has plural pixels arranged therein in atwo-dimensional grid. Each of the pixels produces an analog pixelsignal. The pixel array unit 220 supplies an analog image signalincluding these pixel signals to the AD converting unit 230.

In addition, a circuit including the scanning unit 210 and the pixelarray unit 220 is an example of an image producing unit described in theclaims.

The AD converting unit 230 is a component that converts the image signalinto digital image data (frame). The AD converting unit 230 supplies theproduced frame to the pre-processing unit 240.

The pre-processing unit 240 is a component that executes a predeterminedprocess for the frame as a pre-process. The pre-processing unit 240supplies the frame after undergoing the pre-process to the memorycontroller 260. Furthermore, in the pre-process, the pre-processing unit240 detects a change of the scene in the moving image and sets aspecific period including the timing of the change as a high-speedshooting period. The pre-processing unit 240 thereafter produces ahigh-speed shooting period flag that indicates whether or not thepresent time point is in the high-speed shooting period, and suppliesthe high-speed shooting period flag to the managing unit 250. Thehigh-speed shooting period flag is, for example, set to be in anON-state during the high-speed shooting period and set to be in anOFF-state during any period other than the high-speed shooting period.

The managing unit 250 is a component that manages the overall imagingelement 200. In the high-speed shooting period, the managing unit 250controls the scanning unit 210 to cause the pixel array unit 220 todrive in the high-speed shooting mode when an empty area is present inthe frame buffer 270. On the other hand, in the case where no empty areais present, or outside the high-speed shooting period, the managing unit250 causes the pixel array unit 220 to drive in the normal shootingmode.

Furthermore, in the high-speed shooting mode, the managing unit 250supplies a write address to the memory controller 260 and causes theframe buffer 270 to retain the frame. Furthermore, the managing unit 250produces, for each frame, a time stamp that indicates the reproductiontime of frame, and supplies the time stamp to the output interface 290.Thereafter, in the preview mode, the managing unit 250 supplies a readaddress to the memory controller 260 and causes the memory controller260 to execute extraction of the frame from the frame buffer 270.

The memory controller 260 is a component that controls the frame buffer270. When the write address is supplied from the managing unit 250, thememory controller 260 stores the frame at this address as a bufferingframe. When the read address is thereafter supplied from the managingunit 250, the memory controller 260 reads the buffering frame from thisaddress and supplies the buffering frame to the post-processing unit280.

Furthermore, the memory controller 260 supplies the frame at a low framerate from the pre-processing unit 240 to the post-processing unit 280 asa preview frame.

The frame buffer 270 is a component that retains the frame. For example,a DRAM (Dynamic Random Access Memory) is used as the frame buffer 270.In addition, the frame buffer 270 is an example of a buffer described inthe claims.

The post-processing unit 280 is a component that executes apredetermined process as a post-process for the buffering frame and thepreview frame from the memory controller 260. The post-processing unit280 supplies the frame after undergoing the post-process to the outputinterface 290.

The output interface 290 is a component that outputs the frame. In thepreview mode, the output interface 290 outputs the preview frame to thedisplaying unit 120 and outputs the buffering frames to the recordingunit 140. On the other hand, in the shooting mode, the output interface290 outputs the preview frame to the displaying unit 120 and therecording unit 140. In addition, the output interface 290 is an exampleof an output unit described in the claims.

[Example of Configuration of Pre-Processing Unit]

FIG. 3 is a block diagram depicting an example of the configuration ofthe pre-processing unit 240 in the first embodiment. The pre-processingunit 240 includes a gain adjusting unit 241, a clamping process unit242, and a scene change detecting unit 243.

The gain adjusting unit 241 is a component that adjusts the level ofpixel data using a predetermined gain. The gain adjusting unit 241supplies the pixel data after being adjusted, to the clamping processunit 242.

The clamping process unit 242 is a component that executes a clampingprocess of fixing the black level of the pixel data. The clampingprocess unit 242 supplies the pixel data after undergoing the clampingprocess, to the scene change detecting unit 243.

The scene change detecting unit 243 is a component that detects presenceor absence of a change of the scene. The scene change detecting unit 243compares consecutive plural frames with each other and detects presenceor absence of any change of the scene. The scene change detecting unit243 thereafter sets a specific period including the timing at which thescene changes, as the high-speed shooting period and produces thehigh-speed shooting period flag. The scene change detecting unit 243supplies the high-speed shooting period flag to the managing unit 250and supplies the frame to the memory controller 260.

In addition, the pre-processing unit 240 executes the gain adjustmentprocess, the clamping process, and the scene change detection while thepre-processing unit 240 may be configured to avoid executing any one ormore of these. Furthermore, the pre-processing unit 240 may furtherexecute processes other than these. Furthermore, the imaging element 200already transitions into the high-speed shooting mode when any change ofthe scene is detected while the imaging element 200 may transition intothe high-speed shooting mode in accordance with an operation of a user.In this case, the pre-processing unit 240 does not need to detect anychange of the scene. Furthermore, the scene change detecting unit 243may refer to the frames accumulated in the frame buffer during thehigh-speed shooting and may select the frame to be output, based on amotion of the object. In this case, all of the buffered frames are notalways output and only the frames in a section with a hard motion of thebuffered frames are output by the output interface 290. The frames thatare not output, of the buffered frames are deleted or overwritten on.

[Example of Configuration of Frame Buffer]

FIG. 4 is a diagram depicting an example of the configuration of theframe buffer 270 in the first embodiment. The frame buffer 270 includesan A-area 271 and a B-area 272. The respective A-area 271 and B-area 272can retain N (N is an integer) frames.

[Example of Configuration of Managing Unit]

FIG. 5 is a block diagram depicting an example of the configuration ofthe managing unit 250 in the first embodiment. The managing unit 250includes a time stamp producing unit 251 and an address managing unit252.

The address managing unit 252 determines whether or not an emptycapacity in either the A-area 271 or the B-area 272 exceeds apredetermined threshold value in the high-speed shooting period. In thecase where the address managing unit 252 determines that an emptycapacity exceeding the threshold value is present, the address managingunit 252 sets a high-speed shooting enabling signal to be “enable” andcauses the frame to be produced in the high-speed shooting mode.Concerning the above, the high-speed shooting enabling signal is asignal that instructs as to whether or not the pixel array unit 220 isdriven at a high frame rate. Furthermore, in the case where the addressmanaging unit 252 determines that an empty capacity exceeding thethreshold value is present in either of the areas, the address managingunit 252 produces an empty write address in the area and supplies thewrite address to the memory controller 260. This write address isproduced every time a frame is produced, and the frame is retained inthe frame buffer 270 in order of the production thereof.

Outside the high-speed shooting period or in the case where no emptycapacity exceeding the threshold value is present even in the high-speedshooting period, the address managing unit 252 sets the high-speedshooting enabling signal to be “disable” and causes the frames to beproduced in the normal shooting mode.

In the preview mode, the address managing unit 252 produces a readaddress at which buffering frame is retained, in order of the retentionof the frame and supplies the read address to the memory controller 260.The frames are read in the order of their retention based on the readaddresses. The memory controller 260 deletes the read frame, from theframe buffer 270.

The time stamp producing unit 251 is a component that produces a timestamp for each frame based on a scanning control signal and thehigh-speed shooting enabling signal. The time stamp producing unit 251supplies the produced stamp to the output interface 290. The time stampis attached to the corresponding frame in the output interface 290.

[Example of Configuration of Post-Processing Unit]

FIG. 6 is a block diagram depicting an example of the configuration ofthe post-processing unit 280 in the first embodiment. Thepost-processing unit 280 includes a re-mosaic process unit 281 and ascaling process unit 282.

The re-mosaic process unit 281 is a component that executes a re-mosaicprocess for the respective buffering frame and preview frame. There-mosaic process unit 281 supplies the frames after undergoing there-mosaic process to the scaling process unit 282.

The scaling process unit 282 is a component that executes a scalingprocess of changing the size of a frame. The scaling process unit 282supplies the frame after undergoing the scaling process to the outputinterface 290.

In addition, the post-processing unit 280 executes the re-mosaic processand the scaling process while the post-processing unit 280 may beconfigured not to execute either of these processes. The post-processingunit 280 may further execute processes other than these processes (suchas a defect correction process).

FIG. 7 is an example of the state transition diagram for the imagingapparatus 100 in the first embodiment. The states of the imagingapparatus 100 include a normal shooting mode 610, a high-speed shootingmode 620, and a preview mode 630.

The imaging apparatus 100 transitions into the preview mode 630 when thepower source thereof is turned on. In the preview mode 630, the imagingapparatus 100 extracts the buffering frame from the frame buffer 270 ata frame rate lower than that of the high-speed shooting mode (such as 30fps) and stores the buffering frame in the recording unit 140.Furthermore, the imaging apparatus 100 produces a preview frame at aframe rate lower than that of the high-speed shooting mode (such as 30fps) and displays the preview frame.

When the recording start button is thereafter pressed down in thepreview mode 630, the imaging apparatus 100 transitions into the normalshooting mode 610. In the normal shooting mode 610, the imagingapparatus 100 shoots and displays a preview frame at a frame rate lowerthan that of the high-speed shooting mode (such as 30 fps) andconcurrently records the preview frame.

In the normal shooting mode 610, the high-speed shooting period flag isthereafter set to be in the ON-state and, when an empty portion ispresent in the A-area or the B-area, the imaging apparatus 100transitions into the high-speed shooting mode 620. In this high-speedshooting mode, the imaging apparatus 100 shoots a frame at a frame ratehigher than that of the normal shooting mode (such as 960 fps) andbuffers the frame. Furthermore, the imaging apparatus 100 displays thepreview frame at a low frame rate (such as 30 fps).

Furthermore, in the high-speed shooting mode 620, when the high-speedshooting period flag is set to be in the OFF-state, the imagingapparatus 100 transitions into the normal shooting mode 610. Concerningthe above, the duration of the high-speed shooting period is set to be avalue to the extent that the area for the buffering does not overflow.For example, 960 frames can be retained in the respective A-area andB-area and, in the case where the high-speed shooting is executed at 960fps, a period not exceeding one second is set as the high-speed shootingperiod.

Furthermore, in the normal shooting mode 610 and the high-speed shootingmode 620, when a recording stop button is pressed down, the imagingapparatus 100 transitions into the preview mode 630.

In addition, the imaging apparatus 100 starts the extraction of thebuffering frame when the recording is stopped while the imagingapparatus 100 may start the extraction of the buffering frame when thedisplaying of the preview frame is stopped. In this case, for example, apreview stop mode is further added. When a button to display a setscreen is pressed down or when a period that has no operation executedtherein and whose duration is a specific time period or longer elapses,the imaging apparatus 100 transitions into the preview stop mode. In thepreview stop mode, the imaging apparatus 100 stops the shooting and thedisplaying of the preview frame and extracts the buffering frame.

FIG. 8 is a timing chart depicting an example of an operation of theimaging apparatus 100 in the first embodiment. When the recording startbutton is pressed down, the imaging apparatus 100 produces a previewframe every time a cycle of a synchronization signal such as a verticalsynchronization signal VSYNC elapses. The vertical synchronizationsignal VSYNC is a cyclic signal that indicates the timing to produce aframe. The imaging apparatus 100 thereafter displays and records apreview frame.

When the scene changes at a timing Tc, a period spanning from Ths to Theand including this timing is set as the high-speed shooting period. Inthis period, the imaging apparatus 100 produces and buffers a frameevery time a cycle shorter than that of the normal shooting elapses.Furthermore, the imaging apparatus 100 displays and records the previewframe every time a cycle equal to that of the normal shooting elapses.

When the high-speed shooting period elapses, the imaging apparatus 100produces, displays, and records the preview frame every time the cycleof the vertical synchronization signal VSYNC elapses.

Following the above, after an operation of “recording stop” is executedat a timing Tos, the imaging apparatus 100 produces and displays thepreview frame every time the cycle of the vertical synchronizationsignal VSYNC elapses. Furthermore, the imaging apparatus 100 extractsthe buffering frame from the frame buffer 270 and records the bufferingframe in the recording unit 140 every time the cycle of the verticalsynchronization signal VSYNC elapses.

The application executing unit 150 thereafter refers to the time stampof the respective recorded preview frames and recorded buffering frames,and establishes recording frames by transposing these frames to be inorder of their shooting. For example, the case is assumed where thehigh-speed shooting is executed at 120 fps in 1/15 second from the timewhen a “second” preview frame is shot to the time when a “fourth”preview frame is shot. In this case, seven frames of “2_1,” “2_2,”“2_3,” “3,” “3_1,” “3_2,” and “3_3” are buffered. The applicationexecuting unit 150 deletes the buffering frame of “3” that overlaps withthat of the preview frames and inserts the buffering frames of “2_1,”“2_2,” and “2_3,” between the preview frames of “2” and “3.”Furthermore, the application executing unit 150 inserts the bufferingframes of “3_1,” “3_2,” and “3_3,” between the preview frames of “3” and“4.”

In addition, the imaging element 200 also buffers the frames thatoverlap with the preview frames, as buffering frames during thehigh-speed shooting while the imaging element 200 may be configured tobuffer no overlapping frames. In this case, for example, because theframe of “3” of “2_1,” “2_2,” “2_3,” “3,” “3_1,” “3_2,” and “3_3”overlaps, the frame of “3” is not retained. The duration time of thehigh-speed shooting can thereby be extended. In this case, theapplication executing unit 150 does not need to delete any bufferingframe that overlaps with any of the preview frames.

As exemplified in FIG. 8, when the recording is stopped, the imagingelement 200 outputs the buffering frame synchronizing with the verticalsynchronization signal VSYNC and concurrently outputs also the previewframe. The displaying unit 120 can thereby continue displaying thepreview frame without any discontinuation even during the output of thebuffering frame.

Concerning the above, assuming that, when the recording is stopped, theimaging element 200 discontinues the production of the preview frame andoutputs only the buffering frame, the display of the preview frame isdiscontinued and difficulty arises in the next shooting. In contrast,because the imaging element 200 outputs the buffering frame andconcurrently outputs also the preview frame, the displaying unit 120 cancontinue the display of the preview frame.

FIG. 9 is a diagram depicting an example of variation of a capacity ofthe frame buffer 270 when shooting is executed in the first embodiment.When the scene changes at a timing Tc1, a period from Ths1 to The1including this timing is set as a high-speed shooting period. At thetiming Ths1, the imaging apparatus 100 starts the high-speed shootingbecause the A-area and the B-area are empty. During the period up to atiming The1, the imaging apparatus 100 buffers the frames in the A-area.

After a timing Tse1, when the scene changes at a timing Tc2, the periodfrom Ths2 to The2 including the timing is set as a second high-speedshooting period. At the timing Ths2, the imaging apparatus 100 startshigh-speed shooting because the B-area is empty. During the period up tothe timing The2, the imaging apparatus 100 buffers the frames in theB-area.

FIG. 10 is a diagram depicting an example of variation of the capacityof the frame buffer after the shooting comes to an end in the firstembodiment. After the timing The2, when the operation of recording stopis executed at the timing Tos, the imaging element 200 extracts thebuffering frames from the frame buffer 270 at the low frame rate andoutputs the buffering frames to the recording unit 140.

Concerning the above, a configuration including the frame buffer 270that is not divided into the A-area and the B-area is assumed as acomparative example. In this comparative example, no empty portion ispresent in the frame buffer 270 at the timing The1 at which the firstsession of the high-speed shooting comes to an end in FIG. 9. In thecase where it is desired to start the second session of the high-speedshooting, the user has to press down the recording stop button, waituntil an empty portion is present in the frame buffer 270, andthereafter again press down the recording start button. In this manner,the high-speed shooting cannot be consecutively executed in pluralsessions in the comparative example.

In contrast, the imaging apparatus 100 can consecutively execute thehigh-speed shooting in plural sessions as exemplified in FIG. 9 and FIG.10 by disposing two areas in the frame buffer 270 and starting thehigh-speed shooting in the case where an empty portion is present in anyone of the two areas.

In addition, the two areas are disposed in the frame buffer 270 whilethree or more areas can be disposed therein. When the capacity of theframe buffer 270 is a specific capacity, the period of the high-speedshooting in one session becomes shorter while the number of the sessionsto consecutively execute the high-speed shooting can be increased, asthe number of the areas is increased.

FIG. 11 is a graph depicting an example of variation of an accessdestination of each area in the first embodiment. During the high-speedshooting in the first session, a write address indicating an address inthe A-area is sequentially produced every time a frame is produced atthe high frame rate, and the frame is retained at the address.

During the high-speed shooting in the second session, a write addressindicating an address in the B-area is sequentially produced every timea frame is produced at the high frame rate, and the frame is retained atthe address. When the recording thereafter comes to an end, the readaddress is produced in order of the retention and the frame is read.

[Example of Operation of Imaging Apparatus]

FIG. 12 is a flowchart depicting an example of an operation of theimaging apparatus 100 in the first embodiment. This operation isstarted, for example, when an operation of “recording start” isexecuted. The imaging apparatus 100 executes shooting in the normalshooting mode (step S901) and executes an accessing process of accessingthe buffer 270 (step S910).

Then, the imaging apparatus 100 determines whether or not the high-speedshooting period is started (step S902). In the case where the imagingapparatus 100 determines that the high-speed shooting period is started(step S902: Yes), the imaging apparatus 100 determines whether or notany empty portion is present in either the A-area or the B-area (stepS903).

In the case where the imaging apparatus 100 determines that an emptyportion is present in either the A-area or the B-area (step S903: Yes),the imaging apparatus 100 executes a high-speed shooting process ofshooting at the high frame rate (step S920).

In the case where the imaging apparatus 100 determines that thehigh-speed shooting period is not started (step S902: No), in the casewhere the imaging apparatus 100 determines that no empty portion ispresent in either the A-area or the B-area (step S903: No), or afterstep S920, the imaging apparatus 100 determines whether or not theoperation of recording stop is executed (step S904).

In the case where the imaging apparatus 100 determines that theoperation of recording stop is executed (step S904: Yes), the imagingapparatus 100 transitions into the preview mode (step S905) and executesthe accessing process (step S910). The imaging apparatus 100 thereafterdetermines whether or not the operation of recording start is executed(step S906).

In the case where the imaging apparatus 100 determines that theoperation of recording start is not executed (step S906: No), theimaging apparatus 100 repeatedly executes step S910. On the other hand,in the case where the imaging apparatus 100 determines that theoperation of recording start is executed (step S906: Yes), the imagingapparatus 100 repeatedly executes steps S901 and thereafter.

FIG. 13 is a flowchart depicting an example of the accessing process inthe first embodiment. The imaging element 200 determines whether or notthe high-speed shooting mode used (step S911). In the case where theimaging element 200 determines that the high-speed shooting mode is used(step S911: Yes), the imaging element 200 determines whether or not theproduced frame is a preview frame (step S912). In the case where theimaging element 200 determines that the produced frame is a previewframe (step S912: Yes), the imaging element 200 outputs the previewframe and concurrently buffers the preview frame as a buffering frame(step S913).

On the other hand, in the case where the imaging element 200 determinesthat the produced frame is not a preview frame (step S912: No), theimaging element 200 buffers the frame as a buffering frame (step S914).

In the case where the imaging element 200 determines that the high-speedshooting mode is not used (step S911: No), the imaging element 200determines whether or not the preview mode is used (step S915). In thecase where the imaging element 200 determines that the preview mode isused (step S915: Yes), the imaging element 200 outputs the bufferingframe (step S916).

Furthermore, in the case where the imaging element 200 determines thatthe normal shooting mode is used (step S915: No), the imaging element200 outputs the preview frame (step S917). The imaging element 200causes the accessing process to come to an end after steps S913, S914,S916, or S917.

FIG. 14 is a flowchart depicting an example of the high-speed shootingprocess in the first embodiment. The imaging apparatus 100 shoots in thehigh-speed shooting mode (step S921) and executes the accessing process(S910). The imaging apparatus 100 thereafter determines whether or not ahigh-speed shooting period comes to an end (step S922). In the casewhere the imaging apparatus 100 determines that the high-speed shootingperiod does not yet come to an end (step S922: No), the imagingapparatus 100 repeatedly executes steps S921 and thereafter. On theother hand, in the case where the imaging apparatus 100 determines thatthe high-speed shooting period comes to an end (step S922: Yes), theimaging apparatus 100 causes the high-speed shooting process to come toan end.

As above, according to the first embodiment of the present technique,when an empty portion is present in any of the plural areas in the framebuffer 270, the imaging element 200 starts the high-speed shooting andcan therefore execute the high-speed shooting consecutively in pluralsessions.

First Modification Example

In the above first embodiment, the imaging element 200 outputs each onebuffering frame every time a cycle of the vertical synchronizationsignal VSYNC elapses. The time period necessary for an empty portion tobe established in the frame buffer 270 however becomes longer as thenumber of the buffering frames becomes larger. The imaging element 200of a first modification example of the first embodiment differs fromthat of the first embodiment in that the time period for the emptyportion to be established in the frame buffer is reduced.

FIG. 15 is a timing chart depicting an example of an operation of animaging element 200 in the first modification example of the firstembodiment. The imaging element 200 of the first modification examplediffers from that of the first embodiment in that the imaging element200 outputs two buffering frames at one time every time a cycle of thevertical synchronization signal VSYNC elapses in the preview mode. Inaddition, the imaging element 200 may output three or more frames everytime a cycle of the vertical synchronization signal VSYNC elapses.

As above, according to the first modification example of the firstembodiment of the present technique, the imaging element 200 outputsplural frames of the buffering frames every time a cycle of the verticalsynchronization signal elapses and the time period for any empty portionto be established in the frame buffer 270 can therefore be reduced.

Second Modification Example

In the above first embodiment, the imaging element 200 outputs thebuffering frames when the operation of recording stop is executed. Withthis configuration, when no empty portion is present in the frame buffer270, the next high-speed shooting cannot be started as far as therecording is not stopped. The imaging element 200 in the secondmodification example of the first embodiment differs from that of thefirst embodiment in that an empty area is produced in the frame buffer270 during the recording.

FIG. 16 is a timing chart depicting an example of an operation of animaging element 200 in the second modification example of the firstembodiment. The imaging element 200 of the second modification examplediffers from that of the first embodiment in that the imaging element200 outputs a buffering frame every time a cycle of the verticalsynchronization signal VSYNC elapses in the normal shooting mode. Anempty area can thereby be produced in the frame buffer 270 during therecording.

As above, according to the second modification example of the firstembodiment of the present technique, the imaging element 200 outputs thebuffering frames during the recording in the normal shooting mode and anempty area can therefore be produced in the frame buffer 270 evenwithout stopping the recording.

2. Second Embodiment

In the above first embodiment, the imaging element 200 does not outputthe preview frames and the buffering frames in the order of theirshooting. The application executing unit 150 therefore needs to executean editing process of transposing these frames into the order of theirshooting, and the processing amount of the application executing unit150 is increased as the recording time period is increased. An imagingapparatus 100 of a second embodiment differs from that of the firstembodiment in that the processing amount of the application executingunit 150 is reduced.

FIG. 17 is a timing chart depicting an example of an operation of animaging apparatus 100 in the second embodiment. In the normal shootingmode, synchronizing with the vertical synchronization signal VSYNC, theimaging element 200 shoots a frame and outputs the frame to thedisplaying unit 120 as a preview frame, and outputs the frame also tothe recording unit 140 as a recording frame.

In the high-speed shooting mode, the imaging element 200 outputs thepreview frame to the displaying unit 120 at a low frame rate.Furthermore, the imaging element 200 produces a frame at a high framerate, retains the frame in the frame buffer 270, extracts the frame atthe low frame rate in the order of its retention, and outputs the frameas the recording frame.

In the normal shooting mode after the high-speed shooting mode, theimaging element 200 retains a preview frame in the frame buffer 270every time the imaging element 200 produces this preview frame. Theimaging element 200 extracts the frame from the frame buffer 270 at thelow frame rate and outputs the frame as the recording frame, in theorder of its retention. Furthermore, the imaging element 200 outputs thepreview frame to the displaying unit 120 at the low frame rate.

In the preview mode, the imaging element 200 thereafter extracts theframe from the frame buffer 270 and outputs the frame as the recordingframe, at the low frame rate in the order of its retention until theframe buffer 270 becomes empty.

As above, according to the second embodiment of the present technique,the imaging element 200 retains the preview frame after the high-speedshooting, extracts the frame at the low frame rate in the order of itsretention, outputs the frame as the recording frame, and can thereforeoutput the recording frame in the order of its shooting. The applicationexecuting unit 150 therefore does not need to execute the process oftransposing the recording frames into the order of their shooting, andthe processing amount of the application executing unit 150 can bereduced.

In addition, the above embodiments each present an example to embody thepresent technique, and the matters in the embodiments and the mattersspecifying the invention in the claims respectively have correspondencerelations therebetween. Similarly, the matters specifying the inventionin the claims and the matters in the embodiments of the presenttechnique that are given the identical names as those thereofrespectively have correspondence relations therebetween. The presenttechnique is however not limited to the embodiments and can be embodiedby making various modifications to the embodiments within the scope notdeparting from the gist the present technique.

The process steps described in the above embodiments may be understoodas a method that includes the series of steps and, furthermore, may beunderstood as a program to cause a computer to execute the series ofsteps or a recording medium that has the program stored therein. Forexample, a CD (Compact Disc), an MD (MiniDisc), a DVD (Digital VersatileDisc), a memory card, a Blu-ray disc (Blu-ray (registered trademark)Disc), or the like can be used as the recording medium.

It is noted that the effects described herein are not necessarilylimited and any one effect described in the present disclosure may beachieved.

In addition, the present technique can also take the followingconfiguration.

(1)

An imaging element including:

a buffer that has a plurality of areas disposed therein;

an image producing unit that produces an image in the case where anempty capacity of any of the plurality of areas exceeds a predeterminedthreshold value;

a managing unit that causes an area whose empty capacity exceeds thepredetermined threshold value, of the plurality of areas to retain theimage as a buffering image; and

an output unit that extracts the buffering image from the buffer andthat outputs the buffering image, in order of the retention of thebuffering image.

(2)

The imaging element described in the above (1), in which

the image producing unit produces the image as a preview image everytime a predetermined cycle elapses in a predetermined normal shootingperiod and, in the case where an empty capacity of any of the pluralityof areas exceeds the predetermined threshold value in a high-speedshooting period that is different from the predetermined normal shootingperiod, produces the image as a high-speed shooting image every time acycle that is shorter than the predetermined cycle elapses, and

the managing unit causes the high-speed shooting image to be retained asthe buffering image.

(3)

The imaging element described in the above (2), in which

the output unit further outputs the preview image together with thebuffering image every time the predetermined cycle elapses.

(4)

The imaging element described in the above (2) or (4), in which

the managing unit causes the buffer to retain the preview image togetherwith the buffering image, and

the output unit extracts the buffering image and the preview image fromthe buffer and outputs these images, in order of retention of theseimages.

(5)

The imaging element described in any one of the above (2) to (4), inwhich

the output unit extracts the buffering image from the buffer and outputsthe buffering image when a predetermined operation is executed.

(6)

The imaging element described in any one of the above (2) to (5), inwhich

the output unit extracts the buffering image from the buffer and outputsthe buffering image when the high-speed shooting period comes to an end.

(7)

The imaging element described in any one of the above (2) to (6), inwhich

the output unit extracts and outputs the plurality of buffering imagesevery time the predetermined cycle elapses.

(8)

An imaging apparatus including:

a buffer that has a plurality of areas disposed therein;

an image producing unit that produces an image in the case where anempty capacity of any of the plurality of areas exceeds a predeterminedthreshold value;

a managing unit that causes an area whose empty capacity exceeds thepredetermined threshold value, of the plurality of areas to retain theimage as a buffering image;

an output unit that extracts the buffering image from the buffer andthat outputs the buffering image, in order of the retention of thebuffering image; and

a recording unit that records the output image.

(9)

A control method for an imaging element, the control method including:

an image producing step of producing an image in the case where an emptycapacity of any of a plurality of areas in a buffer that has theplurality of areas disposed therein exceeds a predetermined thresholdvalue;

a managing step of causing an area whose empty capacity exceeds thepredetermined threshold value, of the plurality of areas to retain theimage as a buffering image; and

an output step of extracting the buffering image from the buffer andoutputting the buffering image, in order of the retention of thebuffering image.

REFERENCE SIGNS LIST

-   -   100 Imaging apparatus    -   110 Imaging lens    -   120 Displaying unit    -   130 Control unit    -   140 Recording unit    -   150 Application executing unit    -   160 Reproducing unit    -   200 Imaging element    -   210 Scanning unit    -   220 Pixel array unit    -   230 AD converting unit    -   240 Pre-processing unit    -   241 Gain adjusting unit    -   242 Clamping process unit    -   243 Scene change detecting unit    -   250 Managing unit    -   251 Time stamp producing unit    -   252 Address managing unit    -   260 Memory controller    -   270 Frame buffer    -   280 Post-processing unit    -   281 Re-mosaic process unit    -   282 Scaling process unit    -   290 Output interface

1. An imaging element comprising: a buffer that has a plurality of areasdisposed therein; an image producing unit that produces an image in acase where an empty capacity of any of the plurality of areas exceeds apredetermined threshold value; a managing unit that causes an area whoseempty capacity exceeds the predetermined threshold value, of theplurality of areas to retain the image as a buffering image; and anoutput unit that extracts the buffering image from the buffer and thatoutputs the buffering image, in order of the retention of the bufferingimage.
 2. The imaging element according to claim 1, wherein the imageproducing unit produces the image as a preview image every time apredetermined cycle elapses in a predetermined normal shooting periodand, in the case where an empty capacity of any of the plurality ofareas exceeds the predetermined threshold value in a high-speed shootingperiod that is different from the predetermined normal shooting period,produces the image as a high-speed shooting image every time a cyclethat is shorter than the predetermined cycle elapses, and the managingunit causes the high-speed shooting image to be retained as thebuffering image.
 3. The imaging element according to claim 2, whereinthe output unit further outputs the preview image together with thebuffering image every time the predetermined cycle elapses.
 4. Theimaging element according to claim 2, wherein the managing unit causesthe buffer to retain the preview image together with the bufferingimage, and the output unit extracts the buffering image and the previewimage from the buffer and outputs these images, in order of retention ofthese images.
 5. The imaging element according to claim 2, wherein theoutput unit extracts the buffering image from the buffer and outputs thebuffering image when a predetermined operation is executed.
 6. Theimaging element according to claim 2, wherein the output unit extractsthe buffering image from the buffer and outputs the buffering image whenthe high-speed shooting period comes to an end.
 7. The imaging elementaccording to claim 2, wherein the output unit extracts and outputs theplurality of buffering images every time the predetermined cycleelapses.
 8. An imaging apparatus comprising: a buffer that has aplurality of areas disposed therein; an image producing unit thatproduces an image in a case where an empty capacity of any of theplurality of areas exceeds a predetermined threshold value; a managingunit that causes an area whose empty capacity exceeds the predeterminedthreshold value, of the plurality of areas to retain the image as abuffering image; an output unit that extracts the buffering image fromthe buffer and that outputs the buffering image, in order of theretention of the buffering image; and a recording unit that records theoutput image.
 9. A control method for an imaging element, the controlmethod comprising: an image producing procedure of producing an image ina case where an empty capacity of any of a plurality of areas in abuffer that has the plurality of areas disposed therein exceeds apredetermined threshold value; a managing procedure of causing an areawhose empty capacity exceeds the predetermined threshold value, of theplurality of areas to retain the image as a buffering image; and anoutput procedure of extracting the buffering image from the buffer andoutputting the buffering image, in order of the retention of thebuffering image.